Refrigeration



Sept. 13, 1938. c. T. ASHBY 2 129982 REFRIGERATION Filed Dec. 8, 1936INVENTOR.

Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE.

%129382 BEFRIGERATION Deiaware Application December 8, 1936, Serial No.114,'!31

2 Ciaims.

My invention relates to absorption type refrigeration systems making useof evaporation of refrigerant fluid in the presence of inert gas" and itis an object of the invention to provide a refrigeration system -of thistype having an improved arrangement for storage of reserve gas in thesystem as will appear from the following description and accompanyingdrawing in which the single figure illustrates a refrigeration systemembodying the invention.

The system shown is generally like that described in U. S. Patent1,609,334 to von. Platen and Munters and is made up of a number of steelvessels and pipes welded together to form an hermetically sealed system.All the spaces of the system are in open and unrestricted communica-'tion so that all parts are at the same total pressure. The systemcontains hydrogen and a water solution of ammonia. Other suitable fluidsmay be used.

The parts of the system include a generator n, a condenser Il, anevaporator !2, an absorber !3,

and a hydrogen reserve Vessel M, usually referred to as a pressurevessel. The evaporator |2 is located 'n an insuiated refrigeratorstorage compartment '15 and comprises a pipe coil having a lower portion!6 embedded in an aluminum castv ing and an upper portion l'l providedwith heat transfer fins. The aluminum casting provides a freezingcompartment having shelves ufor ice ireezing trays or the like and thelower part !6 'of the evaporator may be referred to as the lowtemperature or freezing portion. The upper finned portion l 'I of theevaporator cools air in the refrigerator compartment !5.

The condenser* H comprises a flnned pipe coil for air cooling and has anupper portion s and a lower portion IS. The upper portion s is connectedby a conduit 20 to the upper section I'I of the evaporator z, and thelower condenser portion l9 is connected by a conduit !I tothe lowerevaporator section IS. s

The generator o is heated by a gas burner 22 arranged so that the fianeis projected into the generator heating flue 23. Ammonla vapor expelledfrom solution by beat in the generator III liquid. The liquid ammoniaflows from the lower condenser IS through conduit Zi to the low temperature evaporator section !6.

Hydrogen crculates through and between the evaporator' !2 and theabsorber !3 by way of'a gas heat exchanger 28. In the evaporator, theliquid ammonia evaporates and difiuses into the hydrogen, producing a.refrigeration efiect. In the absorber l3. ammonia vapor is absorbed outof the rich gas by weakened absorption solution. The absorber is cooledby a vaporizaton-condensation circuit containing a suitable volatilefluid such as methyl chloride and comprising a cooling coil 29 in heatexchange relation with the absorber and connected to an air-cooledcondenser 30. The gas circulation between the evaporator |2 and theabsorber |3 occurs as a result of the difierence in weights of thecolumns of the rich and Weak gas, the column of gas flowing from theevaporator to the absorber and containing the greater amount of theheavier ammonia vapor being heavier than the column of Weak gas fiowingfrom the absorber to the evaporator. The described members forming thegas circuit are connected in such a manner that the gas flows upwardlythrough the evaporator z so that the partial pressure of ammonia vaporin the lower evaporator section IS is less than the partial pressure ofammonia vapor in the high temperature section l'l which is the reasonfor the difference in temperatures of these evaporator sections. Liquidammonia whichenters the upper evaporator section Il also flows into thelow temperature section IS so that this liquid is precooled in the upperevaporator section l'l before entering the low temperature section ISfrom the condenser temperature to the temperature o the evaporatorsection l'l.

The absorption solution' is circulated through and' between thegenerator o and the absorber !3 by way of a liquid'heat exchanger 3l,and circulation of the solution is caused by the lifting action'of vaporformed in a chamber 32' of the generator which raises liquid through ariser 33 intothe generator stand-pipe 31 where the liquid level is suchthat solution may overfiow therefrom into the absorber. a

` The hydrogen reserve vessel or pressure, vesse M comprises ahorizontally elongated vesselar- 'anged at a slight angle at a levelabove the condenser drain conduits 20 and 2l. The high end of thepressure vessel M is connected by a conduit 34 to the absorber l3. Theoutlet end of the lower condenser section s is connected by a conduit i35 to the upper part of the other end of 'the pres e denser to theevaporator-absorber gas circuit.

The lower end oi' the pressure vessel N is connected by a conduit 36 tothe drain conduit ll.

The upper end of conduit 3! extends into the pressure vessel ll and isopen a slight distance above the lower end thereof so that liquid willbecome accumulated in the lower end oi the pressure'vessel ll beforeoverflowing through conduit 36 and thence through conduit z into theupper end of the evaporator !2. During operation of the system underhigh room temperature conditions, the pressure vessel Il tunctions as anextension of the condenser. Under these conditions, ammonia vapor entersthe pressure vessel ll from the condenser II and displaces reservehydrogen rrom the pressure vessel through conduit ,34 into the gascircuit. The ammonia vapor condenses in the pressure vessel, accumulatesin the lower end thereof and overflows through conduit 36 into theevaporator I2. The quantity ot liquid ammonia thus held out ofcirculation in the pressure vessel under these conditions causesabsorption solution in the generator-absorber circuit to be at a loweraverage concentration. Under medium and low room temperature conditions,reserve hydrogen returns to the pressure vessel through conduit 34 asammonia vapor is removed therefrom and the accumulated liquid ammoniaevaporates and returns into circulation so that the averageconcentration of solution is increas'ed. This weakening of the solutionin a warm room is to obtain a desired capacity to take care of the loadunder these conditions. The increase in concentration oi' solution atmedium and cool room temperatures results in greater efllciency ofoperation under conditions encountered during the greater part of thetime ot operation.

In the above arrangement I have provided a drain conduit 36 from thepressure vessel ll to the upper part of the evaporator which is separatefrom the conduit 35 for vapor from the condenser to the pressure vessel.Thus; liquid ammonia from' the pressure vessel Mais delivered throughconduit 36 and conduit to the high' temperature portion I'I of theevaporator where it is precooled before entering the Ireezing por-` tionli oi the evaporator. This improvement results in greater reirigerationat a ireezing temperature in the evaporator section li obtained fromliquid ammonia entering 'the vaporator from the pressure vessel.

What is claimed 15:,

'1. Absorption rei'rigeration apparatus including an evaporatorconstructed and arranged for upward flow oi' gas therethrough andcontinuously downward flow-of liquid in the presence of the gas, anabsorber, members iorming a circuit for gas through and between saidevaporator and absorber, a generator, members connecting said generatorand absorber ior circulation of absorption liquid therethrough andtherebetween,"

said vessel to said gas circuit, and a-conduit for liquid from saidvessel to the upper part oi' said evaporator, i 4 x 2. Absorptionrefrigeration apparatus containing inert gas and having a circuit forthe gas including an evaporator constructed and arranged for flow of gastherethrough and downward flow of liquid in the presence of the gas, acondenser, a conduit for conducting liquid formed in a first part 'ofsaid condenser to the upper part o! said evaporator, a conduit forconducting liquid formed in a second part of said condenser to a lowerpart of said evaporator, a gas storage vessel at a level above sai'devaporator, a conduit from the outlet end of said condenser to saidvessel, a conduit from said vessel to said gas circuit, and a conduitfor conductng liquid from said vessel to the upper part of saidevaporator,

the flow of gas in said circuit being such that the upper part of saideva'porator is at a higher temperature than said lower part', wherebyliquid from the first partof said condenser and liquid !rom said gasstorage vessel is precooled at the upper part of the evaporator beforeentering the lower part oi the evaporator.

CARL T. Asani.

